1. Field of the Invention
The present invention relates to a field emission device, and in particular to a double-sided light-emitting field emission device and method of manufacturing the same.
2. The Prior Arts
The Field Emission Display Technology incorporates and makes use of the technology of carbon nanotube, so that it is able to achieve great breakthrough and developments in various applications. In addition, due to its spontaneous light-emitting characteristics, the field emission device can not only be utilized as field emission display, but it can also be widely used as light-emitting device in backlight module or illumination light.
In general, the basic structure of field emission device is composed of a phosphor plate serving as an anode, and a carbon nanotube serving as a cathode. As shown in FIG. 1, the field emission device includes two glass substrates, an upper substrate 12 and a lower substrate 10, and a spacer 14 is disposed in-between as a support, so that the space between substrates 10 and 12 is in a vacuum state. The upper substrate is the so-called anode plate, that is provided with an electrode 16 and a layer of phosphor 18 and can be excited by electrons to emit light; while the lower substrate is a cathode plate, composed of an electrode 20 and a field emission array (FEA) 22, that can emit electrons by means of field emission principle. Therefore, the operation principle of the field emission device is that the cathode plate can emit electrons by means of the field emission principle, and that are accelerated by the electrical field to impact on and agitate the phosphor layer on the anode plate to emit lights.
Presently, the field emission device can be classified into a two-electrode type or a three-electrode type depending on the electrode structure, while for its driving and operation, Direct Current (DC) power supply is utilized. However, regardless of the type of electrodes, their common characteristics are that, they are all single-sided light emitting field emission light source, and thus having limited applications. Moreover, since presently, the field emission device is driven by DC voltage, charges tend to accumulate on the electrode to produce arcing effect; or the service life of the carbon nanotube is reduced considerably due to long period impact of electrons on the carbon nanotube.
Therefore, presently, the design and performance of the field emission device of the prior art is not quite satisfactory, and it has much room for improvements.